Giant Jupiter Pays a Visit

All hail and behold this sky king!

By Bob Berman
August 17, 2010
Jupiter Planet

In the latter half of 2010 Jupiter will be making it’s brightest, closest appearance in over 45 years! Find out why Jupiter will be so close to Earth, and where you can see it! Then, check out our fascinating facts about Jupiter.

Jupiter’s 2010 Appearance

  • Not since 1963 has Jupiter been so close, so bright, so easily seen—a result of its slow, oval orbit around the Sun that will take nearly 12 Earth years.
  • Each year, Jupiter visits a different one of the 12 zodiacal constellations (making it the easiest planet to track), and for 1 month each year, the planet appears both opposite (or, in opposition to) the Sun and at its position closest to Earth. This combination results in a best-viewing time for us.
  • Of course, some “bests” are better than others. When Jupiter’s orbit traverses the lower, or southern, zodiac constellations (e.g., Scorpius), the view from Earth appears to be through smudgier air because people are gazing through more of Earth’s atmosphere. Conversely, when Jupiter is in the higher constellations (Taurus or Gemini), we see the planet with much less distortion. (In the United States and Canada, Hawaii is the only place from which Jupiter can be seen to reach its zenith.)
  • From 2010 through 2015, Jupiter will be in northern constellations, with minimal distorting air.

How to Find Jupiter

  • Jupiter advances a month each year. In recent years (2007, 2008, and 2009), Jupiter was best viewed in June, July, and August, respectively. In 2010, it is at its best in September (its closest approach is on September 20, while its opposition is on September 21). It will hover just 367 million miles away and shine at magnitude –2.5.
  • If you are busy or Mother Nature fails to provide clear skies on these nights, don’t despair. The sky king is out most of the night and visible 2 to 3 months before and after opposition—in this case, the entire last half of the year.
  • Finding Jupiter should be easy. Beginning in mid-August, look halfway up the southern sky for the night’s brightest star. This is Jupiter! Dazzling and astonishingly conspicuous against the faint stars of Pisces, it will stand at its highest at 2:00 a.m. (In July, early birds can catch a glimpse at 4:00 a.m.)
  • As the year winds down, Jupiter will be at its best earlier each month: at midnight in September (look for green Uranus hovering nearby in midmonth), at 10:00 p.m. in October, at 7:00 p.m. in November, and at nightfall in December. Want to make an appointment? Get the planet’s rise and set times in your zip or postal code at
  • No one needs to miss this night show. Even the most inexpensive backyard telescope or steadily braced binoculars will inspire ooohs and ahhhs. Jupiter reveals more detail through amateur instruments than any other planet (60¥ magnification is ideal). If you are not equipped, contact an astronomy club or a university about getting a look through a lens.

In 2010, the quadricentennial of Galileo’s heavenly discoveries, the view—by Jove!—should be nothing short of amazing!

Did You Know? Jupiter Facts

  • Jupiter reigns over a miniature solar system of at least 79 moons, including huge and ever-changing Io, Europa, Ganymede, and Callisto (named the Galilean Satellites in Galileo’s honor).
  • Its rotation, which is faster than that of any other planet, creates streaks: dark areas (belts) indicate rising clouds and gases; light areas (zones) indicate where belts sink.
  • It spins fast at its equator and slowly at its poles; where the momentums clash, gaseous layers produce violent eddies, curlicues, swirls, white spots, and the famous Great Red Spot—a hurricane three times the size of Earth. (You can see this on nights when Earth’s air is steady.)

Jupiter by the Numbers

  • Diameter: 11 Earths
  • Mass (quantity of matter): 318 Earths
  • Volume: 1,312 Earths
  • Length of year: 11.86 Earth years
  • Length of day: 9 hours 56 minutes
  • Surface temperature: –234°F
  • Density: 1⁄4 of Earth’s
  • Gravity: 2.4 times stronger than on Earth (a
  • 100-lb. person would weigh 240 lbs. on Jupiter)
  • Magnetic force: 14 times stronger than Earth’s
  • Average distance from the Sun: More than 5 times Earth’s
  • Closest distance to Earth: 367 million miles
  • Brightness, on average: Magnitude –2.3
  • Natural satellites (moons): At least 79


The 2010 Old Farmer's Almanac


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